There are many products, as exemplified by paper tissue, toweling and napkins, etc., which are commonly provided to consumers in stacked form as packs of folded or interfolded individual sheets. These packs of stacked sheets are often staple items which must be produced at very low cost. Producing such products at low cost typically requires the use of high-speed processes and equipment. Such processes are not limited to the production and delivery of paper products, but are widely used in the production of other products such as foil, textile, synthetic sheeting and other industries.
Such products are often formed from one or more continuous webs of materials or from one or more streams of sheets which are folded in a folding apparatus into the desired configuration and deposited in a stacking region extending downstream from the folding apparatus. The stack of sheets in the stacking region is then periodically separated into packs having a desired number of sheets.
Experience has shown that the steps of cutting individual sheets from a web or webs of material, and folding or interfolding the individual sheets to form a stack of folded sheets can be accomplished at higher speeds than subsequent downstream processes such as: separating a stack of the folded material into individual packs having a desired number of sheets; performing secondary folding of a lead or trailing sheet of each pack; and delivering the completed pack to downstream packaging equipment used to wrap or otherwise prepare the completed packs for delivery and sale.
In the past, a variety of approaches have been utilized for: separating stacks of folded sheets into packs; performing any necessary secondary folding operations; and transporting the completed packs to downstream processing equipment. Some of these prior approaches are illustrated in the following US patents which are commonly assigned to the assignee of the present invention: U.S. Pat. No. 4,770,402 to Couturier; U.S. Pat. No. 4,874,158 to Retzloff; U.S. Pat. No. 6,641,358 to Schmidt et al.; and U.S. Pat. No. 6,322,315 to Schmidt et al.
Although the apparatuses and methods taught by Couturier and in other prior approaches as exemplified by the US patents listed above have been successful and commercially viable in the past, further improvement is desirable. Specifically, it is desirable to provide a separation method and apparatus which is operable at higher speeds than can be achieved using prior approaches. Also, it is desirable to provide improved separation methods and apparatuses having a more straightforward construction and operation, ideally having fewer components, which can be produced and operated at lower cost and with higher efficiency and reliability.
Prior separating methods and apparatuses have also generally been limited to use with folded sheets issuing along a substantially vertically oriented folded sheet path to form a stack in which the successive sheets rest vertically upon one another. It is desirable to provide an improved apparatus and method for separating stacks of sheets oriented in a direction other than vertical, and particularly desirable to provide a method and apparatus for separating a horizontally-directed stack of sheets into individual packs.